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In urban areas, water is usually provided through piped systems from specific sources to consumers. Cities, towns, and peri-urban settlements typically benefit from piped systems, while rural areas rely on water supplies from surface sources like rivers and canals, as well as ground sources such as wells and tube wells. When traditional methods fail, alternative water supply systems emerge in both urban and rural areas. This paper addresses the question of whether alternative water supply arrangements are sustainable in terms of system reliability, consumer acceptance, cost-effectiveness, convenience, perceptions of service levels, and ease of access to service providers. This paper examines the status of alternative water supply arrangements in Turkana County, Kenya, and Orangi in Karachi, Pakistan, using qualitative methods. It highlights that underprivileged communities commonly turn to alternative water supply arrangements when conventional methods are unavailable or underperforming. [ABSTRACT FROM AUTHOR]

ABSTRACTMost rural parts of South Africa’s Limpopo Province are faced with limited water access, provision, and inadequate infrastructure for water reticulation. With over 80% of the provincial population living in rural areas, water availability for domestic and agricultural use has become a source of concern. Rainwater harvesting (RWH) has emerged as an important source of alternative water supply for underserved communities during the summer rainfall season. RWH refers to the collection, storage and conservation of surface runoff for agricultural production and domestic uses. This study assessed the socio-economic characteristics and determinants of RWH practices in rural communities of Limpopo Province. Descriptive statistics were used to describe households’ socio-economic characteristics and logistic regression was used to examine the determinants of RWH practices in rural communities. The analysis was based on a survey of 478 households selected using convenience and purposive sampling techniques. The key findings indicate that a significant number of households (63.8%) practised RWH to augment available water for domestic use, albeit few households used the harvested water for portable use. Further analysis showed that a majority of those who adopted RWH practices were female (64.24%). The results of the empirical models indicate that there is a statistically significant positive relationship between perception, age and level of education in determining the adoption of RWH practices. The findings underline the importance of understanding the adoption of RWH in rural communities and highlight the vital role of education, knowledge, and income in rural communities with limited or no access to a water supply. The study highlights the need for policy to promote the benefits of harvesting rainwater for domestic use.

Sea-level rise, population growth, and changing land-use patterns will further constrain Florida’s already scarce groundwater and surface water supplies in the coming decades. Significant investments in water supply and water demand management are needed to ensure sufficient water availability for human and natural systems. Section 403.928 (1) (b) of the Florida Statutes requires estimating the expenditures needed to meet the future water demand and avoid the adverse effects of competition for water supplies to 2040. This study considers the 2020–2040 planning period and projects (1) future water demand and supplies; and (2) the total expenditures (capital costs) necessary to meet the future water demand in Florida, USA. The uniqueness of this study compared with the previous studies is the introduction of a probabilistic-based approach to quantify the uncertainty of the investment costs to meet future water demand. We compile data from the U.S. Geological Survey, Florida’s Department of Agriculture & Consumer Services, Florida’s Water Management Districts, and the Florida Department of Environmental Protection to project the future water demand and supplies, and the expenditures needed to meet the demand considering uncertainty in the costs of alternative water supply options. The results show that the total annual water demand is projected to increase by 1405 million cubic meters (+15.9%) by 2040, driven primarily by urbanization. Using the median capital costs of alternative water supply projects, cumulative expenditures for the additional water supplies are estimated between USD 1.11–1.87 billion. However, when uncertainty in the project costs is accounted for, the projected expenditure range shifts to USD 1.65 and USD 3.21 billion. In addition, we illustrate how using Modern Portfolio Theory (MPT) can increase the efficacy of investment planning to develop alternative water supply options. The results indicate that using MPT in selecting the share of each project type in developing water supply options can reduce the standard deviation of capital costs per one unit of capacity by 74% compared to the equal share allocation. This study highlights the need for developing more flexible funding strategies on local, regional, and state levels to finance additional water supply infrastructure, and more cost-effective combinations of demand management strategies and alternative water supply options to meet the water needed for the state in the future.

Sea-level rise, population growth, and changing land-use patterns will further constrain Florida's already scarce groundwater and surface water supplies in the coming decades. Significant investments in water supply and water demand management are needed to ensure sufficient water availability for human and natural systems. Section 403.928 (1) (b) of the Florida Statutes requires estimating the expenditures needed to meet the future water demand and avoid the adverse effects of competition for water supplies to 2040. This study considers the 2020–2040 planning period and projects (1) future water demand and supplies; and (2) the total expenditures (capital costs) necessary to meet the future water demand in Florida, USA. The uniqueness of this study compared with the previous studies is the introduction of a probabilistic-based approach to quantify the uncertainty of the investment costs to meet future water demand. We compile data from the U.S. Geological Survey, Florida's Department of Agriculture & Consumer Services, Florida's Water Management Districts, and the Florida Department of Environmental Protection to project the future water demand and supplies, and the expenditures needed to meet the demand considering uncertainty in the costs of alternative water supply options. The results show that the total annual water demand is projected to increase by 1405 million cubic meters (+15.9%) by 2040, driven primarily by urbanization. Using the median capital costs of alternative water supply projects, cumulative expenditures for the additional water supplies are estimated between USD 1.11–1.87 billion. However, when uncertainty in the project costs is accounted for, the projected expenditure range shifts to USD 1.65 and USD 3.21 billion. In addition, we illustrate how using Modern Portfolio Theory (MPT) can increase the efficacy of investment planning to develop alternative water supply options. The results indicate that using MPT in selecting the share of each project type in developing water supply options can reduce the standard deviation of capital costs per one unit of capacity by 74% compared to the equal share allocation. This study highlights the need for developing more flexible funding strategies on local, regional, and state levels to finance additional water supply infrastructure, and more cost-effective combinations of demand management strategies and alternative water supply options to meet the water needed for the state in the future. [ABSTRACT FROM AUTHOR]

The urban-scale impacts of the use of Rainwater Harvesting Systems (RWHS) are little explored within the Brazilian urban and climatic reality. Thus, the objective of this work is to verify the impacts of these systems in reducing runoff and the demand for drinking water, through a case study carried out in a neighborhood in the city of Goiânia-GO. In order to carry out the study, the land use characteristics of the studied region were studied from satellite images, with three batch patterns being defined as study scenarios. The daily residential demand for non-drinking uses of water was calculated from the standard lots and the annual rainfall pattern in the city of Goiânia, which was also characterized by taking a 30-year historical series of daily rainfall data. With these data in hand, daily water balances were calculated using Excel, for commercial reservoirs of 1, 5 and 10 m3, in addition to reservoirs with ideal volumes obtained from the NETUNO software. Two balance models were tested and compared and, from them, analyzes were made of the potential for reducing the annual consumption of drinking water in the neighborhood and hydrological simulations were run to verify the flow damping, with the support of the SWMM program. In general, the RWHS use has positive aspects: it reduces the drinking water demand in the neighborhood (up to 37%). However, when analyzing the reduction of peak flows in the drainage system, it is only significant in scenarios with larger reservoirs, confirming its marginal role in stormwater management. [ABSTRACT FROM AUTHOR]

Globally, freshwater resources are threatened, resulting in challenges for urban water supply and management. Climate change, population growth, and urbanization have only exacerbated this crisis. For the Caribbean, climate change through the impact of increasing temperatures and rainfall variability has resulted in more frequent and intense episodes of disasters including droughts and floods which have impaired the quantity and quality of freshwater supplies. Using Caribbean-specific climate forecasting, it is shown that rainfall totals in Kingston, Jamaica, are expected to reduce by 2030 and 2050 under two RCPs. In addition, the timing of the primary rainy season is expected to shift, potentially impacting water supply security. Analysis of the potential of rainwater harvesting (RWH) to augment supply and enhance water supply resilience shows that in two communities studied in Kingston, it can contribute up to 7% of total water supply. Household storage requirements are about 1 m3 per household, which is feasible. RWH offers the potential to contribute to climate change adaptation and mitigation measures at a household level. Policy, incentives, and increased awareness about the potential of RWH to meet non-potable household demand in Kingston must be improved, as well as efforts to reduce the currently unreasonably high levels of non-revenue water in order to move towards an integrated, sustainable, and climate-resilient urban water supply strategy for the city.

Recently water supply alternative sources, recognized as sustainable and ecofriendly have become popular. This is consequent on the scarcity and increasing demand for water, especially by developing nations characterized by industrialization and increasing population growth. However, the intricacies and overwhelming nature of factors to be considered in reaching a decision on a best alternative has further prompted the emergence of several decision support tools, some of which arouse discrepancies with setbacks. We employ here, the uniqueness of fuzzy TOPSIS (technique for order preference by similarity to ideal solution), a multi-criteria decision approach (MCDA), to aid in deciding the most preferred alternative water supply among, desalination, water borehole, rain water harvesting, reclaimed water, black water, grey water and water importation. This method is reckoned for its ease in handling both quantitative and qualitative data. Moreover it also overcomes the uncertainties in expert opinions usually encountered in the decision process due to the numerous variables, criteria and attributes that interplay in achieving sustainability. Results from analysis on data aggregation, normalization and performance ratings, coupled with the weighted distance from the positive and negative ideal solutions indicated that borehole ranked topmost followed by rain water harvesting (RWH). These revelations are apt to all stakeholders in the water delivery sector and in deliberations on the paradigm shift to water conservation and management measure. [ABSTRACT FROM AUTHOR]

This review examines the prospects of a decentralised hybrid rainwater-greywater system to simultaneously alleviate water scarcity and address technical, environmental, and cost constraints. This includes (1) a review on the physicochemical and microbiological characteristics of rainwater and greywater to determine the necessary treatment options; (2) a review of individual components and potential treatment trains for hybrid systems; and (3) an evaluation of configurations for hybrid systems. The literature review reveals that both untreated rainwater and greywater are highly variable in quality and quantity, and so an equalisation basin is proposed to normalise influent into a hybrid system. Both rainwater and greywater should not be reused without treatment due to the presence of pathogens such as Aeromonas , Salmonella , Pseudomonas , and Staphylococcus . Based on the literature, hybrid systems are categorised under three configurations: (a) separate treatments of rainwater and greywater; (b) rainwater reused in washing machines prior to reuse as greywater; and (c) combined treatment of rainwater and greywater. In all three designs, rainwater requires only first-flush diversion and disinfection. Combined rainwater-greywater mixtures should be treated as greywater. Greywater requires chemical, biological, and physical treatment to meet non-potable reuse standards. Chemical processes are effective at removing solids, organics, and surfactants in light greywater, whereas aerobic biological processes are effective at organics removal in mixed and dark greywaters with high organic strength. Physical processes, particularly membrane filtration, are recommended for polishing effluents from chemical or biological treatment as membranes foul frequently and are costly. Subsequently, a combination of ozone or UV with chlorine is recommended to eradicate chlorine-resistant Cryptosporidium oocysts from hybrid rainwater-greywater systems and prevent microbial regrowth. [ABSTRACT FROM AUTHOR]

The Swan Coastal Plain in Western Australia has been undergoing rapid urban growth and with it comes two primary water related concerns. The first is the spread of development into areas with shallow water tables which requires costly water management to control groundwater level rise; the second is the limited groundwater allocation available in areas earmarked for development. In regard to the second, a potential water source for developments on low-lying land is subsurface drainage that has been installed to control groundwater levels. This research project is being undertaken at two urban developments on low-lying land and includes subsurface drain flow and quality monitoring. The field data will inform numerical hydrogeological and hydrogeochemical models. The objective is to quantify the subsurface drainage volume available as a water resource, and the environmental and operational risk of utilising the resource. The results to date show potential for diverting subsurface flow for direct irrigation in the drier months without the requirement for wet season storage and dry season reuse. Annual subsurface drainage flows provide multiple times the annual irrigation demand if wet season flows are stored and reused by aquifer storage and recovery, and provides opportunity for beneficial use of excess water. [ABSTRACT FROM PUBLISHER]

Nutrient impairment of Florida's surface waters due to urban stormwater runoff is a growing concern, resulting in the development of new regulatory policies. Several best management practices (BMPs), such as stormwater retention/detention ponds, help reduce the impact of flooding but may not reduce nutrient loadings sufficiently to meet water quality goals. This paper presents the design and implementation of a floating media bed reactor (FMBR) as a supplementary treatment unit for stormwater wet detention ponds to enhance the removal efficiency of total phosphorus (TP) and total nitrogen (TN). This effort mitigates the adverse effects of stormwater runoff on downstream impaired waterbodies. The FMBR was filled with an engineered mixture of adsorption media made of natural and recyclable materials and operates on a 24 h continuous cycle, powered by a small photovoltaic pumping system. Significant reductions in TP and TN were documented across the FMBR achieving varying degree of removal efficiencies for storm and non-storm events with fluctuating temperatures. The outcome expands the state of the art stormwater treatment technology and encourages stormwater reuse as an alternative source of freshwater. [ABSTRACT FROM AUTHOR]

Resource recovery and conservation of resources have been attracting increasing attention in the recent years for finding sustainable solutions to environmental problems. One of such efforts is segregation of domestic wastewater streams as grey, yellow and brown or black water. This enables revaluation of domestic wastewater as an alternative renewable source of water as well as a potential source of plant nutrients, i.e. fertilizers. Reuse of grey water (the stream excluding toilet wastewater) can help reduce the unnecessary utilization of pristine water in line with 'fit for purpose' use and can provide an alternative source for water stressed/scarce areas. Yellow water (human urine) constitutes only 1 % of conventional domestic wastewater by volume yet contains over 80 % of nitrogen, over 50 % each of phosphorus and potassium, hence lending a high potential to be used as fertilizer. Direct and indirect application may be practiced. Ion exchange/adsorption with clinoptilolite is a promising option for indirect use. Recoveries exceeding 90 % have been attained for nitrogen and phosphorus from clinoptilolite exhausted with N&P in yellow water. Preliminary results on pot trials have revealed that the alternative fertilizer produced is comparable to synthetic fertilizers. This paper presents a review focusing on grey water reuse as opposed to reuse after conventional combined collection; and the use of plant nutrients in yellow water as an alternative source of fertilizers. Segregated collection provides a promising route towards sustainability by contributing to 'fit for purpose' use of scarce fresh water resources through the reuse of grey water while providing a means of conservation through the recovery of plant nutrients from 'wastes'. [ABSTRACT FROM AUTHOR]

An effective urban water demand management program can greatly influence both peak and average demand and therefore long-term water supply and infrastructure planning. Although a theoretical framework for evaluating residential indoor demand management has been well established, little has been done to evaluate other water use sectors such as residential irrigation in a compatible manner for integrating these results into an overall solution. This paper presents a systematic procedure to evaluate the optimal blend of single family residential irrigation demand management strategies to achieve a specified goal based on performance functions derived from parcel level tax assessor's data linked to customer level monthly water billing data. This framework is then generalized to apply to any urban water sector, as exponential functions can be fit to all resulting cumulative water savings functions. Two alternative formulations are presented: maximize net benefits, or minimize total costs subject to satisfying a target water savings. Explicit analytical solutions are presented for both formulations based on appropriate exponential best fits of performance functions. A direct result of this solution is the dual variable which represents the marginal cost of water saved at a specified target water savings goal. A case study of 16,303 single family irrigators in Gainesville Regional Utilities utilizing high quality tax assessor and monthly billing data along with parcel level GIS data provide an illustrative example of these techniques. Spatial clustering of targeted homes can be easily performed in GIS to identify priority demand management areas. [ABSTRACT FROM AUTHOR]

A key measure of efficiency in the field of urban water demand is gallons per capita per day of water use. One popular metric, gross gallons per capita per day, can be misleading because it includes nonresidential water uses. As an alternative, this article addresses the calculation of residential water use defined as the product of population and per capita use associated solely with people who are physically present and using water in single-family and multifamily residences at a given time. This approach allows for consistent benchmarking because per capita use multiplied by population yields the actual amount of water delivered to the residential sector. Process models for residential population and indoor and outdoor per capita water use can be used to estimate total residential water use if they incorporate the variability among fixture end uses and irrigable area for every household served by a utility. When this approach was applied to the Sanford, Fla., case study area, the process models predicted single- and multifamily water use with reasonable accuracy. [ABSTRACT FROM AUTHOR]

This article presents a systematic procedure to quantify savings potential of single-family residential irrigation demand management strategies that can be used to evaluate the optimal blend of these strategies to achieve specified goals. Current irrigation practices, irrigable area, and irrigation application rate are derived for each single-family residence based on parcel-level tax assessor’s data linked to customer-level monthly water billing data. Water savings are calculated directly as the difference between current and proposed use after implementation of a management option for each residence. This information is used to develop performance functions that estimate total water savings as a function of the number of implementations for each residence. This procedure allows demand management options to be compared directly with other supply augmentation options when determining the optimal blend. Probabilistic models are derived from benchmark parcel-level datasets for evaluation of other utilities where direct measurements are unavailable. [ABSTRACT FROM AUTHOR]

The Conserve Florida Water Clearinghouse has developed Internet-based software called EZ Guide to assist Florida water utilities in evaluating water use efficiency. This modeling approach estimates single-family outdoor water use for every parcel using a uniform statewide property appraisers' database to estimate irrigated area for each parcel. Billing data are needed to estimate the irrigation application rates for each parcel, although few utilities have used the available data for this purpose. Analyses using these unique databases for a benchmark utility in Florida provide new insights into the overall impact of single-family outdoor water use and cost-effective management options. A key result is that only a small percentage of homes are large irrigators, which makes them candidates for irrigation best management practices. However, this study also shows a dramatic rise in the prevalence of inground sprinkler systems over the past few decades, which has led to increased irrigation application rates. [ABSTRACT FROM AUTHOR]

Abstract: The goal of this research was to evaluate the long-term performance of magnetic ion exchange (MIEX) treatment using bicarbonate as the mobile counter ion (i.e., MIEX-HCO3) and sodium bicarbonate for regeneration. This work is important because there are many unknowns concerning the affinity and regeneration efficiency of bicarbonate-form anion exchange, whereas chloride-form anion exchange (i.e., MIEX-Cl resin) is well-studied. Raw water samples were collected approximately two times per month for one year from a single location on the St. Johns River (SJR), FL, USA. The SJR is characterized by high concentrations of dissolved organic carbon (DOC; 12–26 mg C/L) and bromide (550–1100 μg/L), and is being considered as an alternative drinking water supply. Jar tests were conducted using MIEX-HCO3 resin, and MIEX-Cl resin was used as a baseline for comparison. The same batch of MIEX-HCO3 and MIEX-Cl resin was used for the entire study, which was accomplished by regenerating the resins after each jar test in concentrated solutions of sodium bicarbonate and sodium chloride, respectively, and resulted in 21 regeneration cycles. Maximum removal efficiency was achieved with fresh MIEX-HCO3 resin and virgin MIEX-Cl resin. Both forms of fresh/virgin MIEX resin also had the same affinity sequence with sulfate ≈ UV-absorbing substance > DOC > bromide. The removal efficiency of both forms of MIEX resin decreased as the number of regeneration cycles increased, with MIEX-HCO3 resin showing 7–18% lower removals than MIEX-Cl resin after 21 regeneration cycles. The affinity sequence of regenerated MIEX-HCO3 and MIEX-Cl resins differed from fresh resin with UV-absorbing substances > DOC > sulfate > bromide. Scanning electron microscopy and simulated MIEX-HCO3 treatment under rapidly changing water quality were also used to improve the understanding of bicarbonate-form anion exchange. The major contribution of this research is a systematic study of the extended use of bicarbonate-form anion exchange resin in the context of affinity, regeneration efficiency, and changing water quality. [Copyright &y& Elsevier]

Globally, freshwater resources are threatened, resulting in challenges for urban water supply and management. Climate change, population growth, and urbanization have only exacerbated this crisis. For the Caribbean, climate change through the impact of increasing temperatures and rainfall variability has resulted in more frequent and intense episodes of disasters including droughts and floods which have impaired the quantity and quality of freshwater supplies. Using Caribbean-specific climate forecasting, it is shown that rainfall totals in Kingston, Jamaica, are expected to reduce by 2030 and 2050 under two RCPs. In addition, the timing of the primary rainy season is expected to shift, potentially impacting water supply security. Analysis of the potential of rainwater harvesting (RWH) to augment supply and enhance water supply resilience shows that in two communities studied in Kingston, it can contribute up to 7% of total water supply. Household storage requirements are about 1 m3 per household, which is feasible. RWH offers the potential to contribute to climate change adaptation and mitigation measures at a household level. Policy, incentives, and increased awareness about the potential of RWH to meet non-potable household demand in Kingston must be improved, as well as efforts to reduce the currently unreasonably high levels of non-revenue water in order to move towards an integrated, sustainable, and climate-resilient urban water supply strategy for the city. [ABSTRACT FROM AUTHOR]

This paper examines the capital costs for alternative water supply projects in Florida, the third most populous state in the United States. The increasing scarcity of fresh groundwater in Florida has led to investments in alternative water supply sources, including brackish groundwater, surface water capture and storage, reclaimed water, and stormwater. Expenditures to meet the growing water demand for the 20-year planning horizon are estimated using water demand projections and existing supply estimates from Florida's five water management districts. In the regions where demand projections exceed the existing supply, the districts are required to identify project options to meet the growing water demand while protecting the natural systems. This study uses the database of 645 projects implemented in the past or considered for the future. The Ordinary Least Squares regression model shows that project implementation costs depend on project capacity, type, implementation status, and implementation region. Given the most common project types and project sizes, the total investments to meet the state's future water demand could reach almost $2 billion in the next 20 years. The expenditures necessitate more cost-effective options (such as expanding stormwater use and water conservation). [ABSTRACT FROM AUTHOR]